Steering rack boots are typically in the form of a sleeve of bellows-like form mounted on the tie rod shaft to provide a seal between the shaft and the main housing of the steering rack in order to prevent ingress of dirt, mud, water, and other foreign matter into the housing itself and also into the joint at the inner end of the shaft. The boot is subject to deterioration over a period of time as a result of wear arising from the continual flexing of the boot and also as a result of contamination by oil, grease, and other matter thrown up from the road surface.
To replace a worn boot, the common practice is to disconnect the tie rod end from the steering arm or knuckle of the associated wheel and to remove the existing boot firstly by removing clamps at each end of the boot and then cutting the boot so that it can be pulled away and discarded. The tie rod end which is now free is itself removably connected to the tie rod shaft by a threaded coupling. For many standard types of boot, the tie rod end needs to be removed from the tie rod shaft to permit the fitting of the replacement boot as the boot cannot stretch sufficiently to pass over the tie rod end. This requires the steering rack to be readjusted to the correct steering geometry when the tie rod end is refitted onto the tie rod shaft. An alternative which enables the tie rod end to be maintained in position to preserve the existing steering geometry is to fit a replacement boot with greater stretch (a “stretch type boot”) and to use an aid which facilitates passage of the replacement boot over the tie rod end and onto the tie rod shaft.
Conventionally, that aid is in the form of a plastic cone which snaps tightly onto the tie rod end. This is shown in FIG. 1, in which the tie rod end is designated 2, and the plastic cone is designated 4. FIG. 2 shows the steering rack boot 8 on the tie rod shaft 10 after both of its ends have passed over the cone 4. Although the cone 4 encloses the outer part of the tie rod end 2 and aids the initial movement of the end of the boot 8 onto the tie rod end 2, the main part of the tie rod end 2 is a body of a bulbous shape (shown at 2a) and not all of this is covered by the cone 4. The uncovered part of the tie rod end 2 is not smoothly finished but has rough and sometimes jagged surfaces. The two ends of the boot 8 need to be stretched to pass over the cone 4 and uncovered body part 2a, and due to the roughness of the surface of the body part 2a a lot of force is needed to push each of the ends of the boot 8 over the body part 2a. As the stretched end is under tension during this phase of the fitting, there is a risk of the end being cut by sharp edges or projections on the body part 2a and other uncovered parts of the tie rod assembly while it is being forced across the body part. Moreover, unless the tie rod end 2 is thoroughly cleaned prior to the fitting of the boot 8, any dirt and other foreign matter which is on the tie rod end may be introduced into the interior of the boot during this stage and this matter might enter into the interior of the rack housing and may cause serious damage to the steering mechanism.